Mr. Idaho: I did it yesterday.
Resistance measure on power wires with them disconnected from battery: OL (infinite)
Turned battery ON, crossed fingers and re-connected motor to battery: A very healthy 42V spark ensued.
Turned controller back on and was relieved to find that it still worked.
Haven't reread. Does your controller light up?
Are there any error messages?
FWIW: I had a "dicky" speed sensor connection once, twice, thrice (until I fixed it) and got its error message. It's not supposed to work with such error message but it does. Only problem is you can't change assist levels but, you still have assistance at whatever level it was set at before the sensor disconnected. I think it may also have been possible to stop, change it, and start of with a new level.